/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

package axil.stdlib.collection.function;

import axil.api.AxilObject;
import axil.api.extend.Environment;
import axil.api.extend.Function;
import axil.api.extend.Parameters;
import axil.api.extend.Source;
import axil.engine.function.Functor;
import axil.stdlib.collection.type.Arry;
import axil.stdlib.collection.type.AxilCollection;
import axil.stdlib.collection.type.Dict;
import axil.vm.stack.StackFrame;

import static axil.framework.Functions.*;


/**
 * Return a new collection containing the items in the given collection after
 * application of the given function. For example:
 *
 * 		collect(cart.items, func(item, item.title))
 */
public class Collect implements Function {
	/**
	 * Execute this function with the given arguments. The Axil compiler will
	 * ensure that the number of arguments passed to the function are valid.
	 * If this function fails during execution for any reason, then an exception
	 * is thrown. Returns any Axil object, but not null. Use the Axil.NIL object
	 * for a null value.
	 */
	public AxilObject eval(Environment env, Parameters params, Source source) {
        AxilCollection collection;
        if (params.a() instanceof AxilCollection) {
            collection = (AxilCollection) construct(params.a().getClass());
        } else {
            collection = new Arry();
        }
        Functor func = callable(params.b());
        StackFrame sf = StackFrame.create(params, source, func.ids());
        if (collection instanceof Dict) {
            Dict oldDict = (Dict) params.a();
            for (Object nextKey : oldDict.keys()) {
                sf.a(oldDict.at((AxilObject) nextKey));
                collection.put(pair((AxilObject)nextKey, func.call(env, sf)));
            }
        } else {
            for (AxilObject obj : iter(params.a())) {
                sf.a(obj);
                collection.put(func.call(env, sf));
            }
        }
        return collection.immute();
	}
}
